Solution:

Grid 5.

Explanation:
If you arrange the images as shown in the below image, you will notice that they all are connecting images.

Solution:

It can be done as shown in the picture below.

Solution:

The circled owl is looking away from the rest and hence antisocial.

Solution:

Remove the same 2 matchsticks from each figure and move figure towards left 45 degrees, It forms the letters V W X Y.

Solution:

Pie

Explanation:
This is the bar graph that represents the number (3, 1, 4, 1, 5, 9, 2, 6, 5).
and we know the value of pie is 3.14159265

Solution:

Lucky days are here again.

Explanation:
Lucky + Day + s + R + H + Ear + Again (Flower represent lucky symbol)

Solution:

FORREST GUMP

Explanation:
FOR (four [o'clock]) + REST (person lying in bed) + GUMP ([bubble] gum + p)

Solution:

16

Explanation:
9 [1x1] squares
5 [2x2] squares
1 [4x4] square
1 [4x4] square

9 + 5 + 1 + 1 = 16 squares.

Solution:

It's shown in the picture below.

Solution:

Tank-5

Explanation:
This is a variation of Which Tank Will Fill First Brain Teaser but in this puzzle connection between tank-5 and tank-2 is closed so water will go into tank-5 from tank-1 but not go to tank-2. Therefore tank-5 will be filled first.